1. Field of the Invention
The present invention relates to a personal video recorder (PVR), and more particularly, to a personal video recorder and control method thereof, by which two scrambled transport streams are descrambled.
2. Discussion of the Related Art
Generally, such an encoder as MPEG (moving picture experts group) is used in home appliances field including digital TV, digital camcorder, and the like to reduce both storage and transfer capacities of digital video or audio. Specifically, in digital TV and set-top box (STB), the digital storage system using such a digital storage medium as HDD and DVD (digital versatile disc) is used instead of the analog storage system using conventional VTR (video tape recorder).
The digital camcorder needs an encoder having a complicated standard of MPEG series and should include both encoder and decoder. Lately, a simple compression encoding standard is provided to overcome problems of the MPEG-series encoder that has to perform computation of motion estimation and compensation. The encoding standard of the digital camcorder is disclosed in ‘International standard CEI/IEC 61834-2, Recording—Helical-scan digital video cassette recording system using 6.35 mm magnetic tape for consumer use (525-60, 625-50, 1125-60 and 1250-50 systems)—Part 2: SD format for 525-60 and 625-50 systems’ and is generally called DV (digital video) format.
The conventional PVR function is limited to storing a TV program corresponding to another channel on mainly viewing one specific program, viewing a TV program stored in HDD via time-shift function, or storing/playing back digital TV signals in/from HDD. Demand for a PVR device equipped with processing and storing functions of various video input signals such as a digital camcorder, digital camera, and the like is raised. For this, instead of preparing or combining the respective chips meeting various types, a system price reduction and system integration enhancement via one unified video decoding chip are more efficient.
However, the related art PVR needs a conditional access system (CAS) module to descramble the scrambled transport stream(s). The CAS module is operative in descrambling a transport stream of a pay channel. Yet, the CAS module failing to fit the U.S. open cable PVR standard is unusable.